Oil soluble colors of the anthraquinone series



fatentecl Aug. 26,

UNITED STATES PATENT oerics orn soLUBnncoLons F QUINONE SERIES rviue, and William B. Hardy; N. J., assignors to American Giana mid (lonip'afiy, New York, N. Y., a corpo ration of Malffi 1% fii-aiimig'; uiflpiication October 12, 1945,

-- Serial No. 622,096

oils, gas'olines and other organic solvents, particu' larly in uses where high sblubilitis are required;

The solubili'ty oftlre amino anthraquinones is enhanced if the amino groups" are alkylated: This procedure, however, results in a, satisfactory solubility only in those cases where at leasttwo 'arnino' group's para' to each other are present. These" products are" blue or green, and such' products are known as valuable oil or gasoline colors. It has not been possible heretofore; however," to prepare colors with' equal solubility character istics in the red to viol'et range;

We have found that if alkyl groups are intro duced in the anthraquinone nucleus itself; as well as in the amino-group's; the solubility of the resulting products" is" far greater than one would have expected. Thus, while 1"-amyl amino an thraquinone is relatively little soluble in organic solvents; such as high boiling paraffin oils; the 1- amyl amino-'2 metl'iyl AQ is sombre in" these s61: vents to the extent 1110 to by weight. 'The same relationship holds between 1:5-dialkylamino anthraquinone on the one hand, and 125-dialkylamino-2-methyl anthrauinone on the other. It is surprising that in; a heavy molecule such as the amino anthraquinones' a small group like the methyl should have such major solubilizing influence. r

Thesevery high solubiliti esare .ofgreatt'echni cal importance. They are needed not only to produce very intense shades in oils; waxes; etc, but are also extremely desirable when-paler shades are desired, because they permit the preparation of concentrated master blends? which can then be seqt incor orat th smg h y in la volumes of the liquid to be colored. Heretofore, this was not possible for red and violet shades, for which colors of sumcientl'y high solubility were not available.

These colors may be produced by various means. For instance, the allryl anthraquinone may be chlorinated or nitrated, and the'enegative grouphalogen or nitrobe replaced. with an alkyl fill fi re 99mm Qiif p r'fer d procedure reacts the alpha rirtro alky'l anui aquine'r'ges with' an augyi' airline si na e hydrocarbon. This proeeere has the advan age that the sta ting natal-as are easily and inexpensively prepared on alarge t nts as reaction with the arn'rre p'roc'eeds gm ttfiiy and in du'antitative yields; an the fc'idu't? 5f reaction is" easily isolated in the pure sta e by steam distillation or the solvent andxteatime: the entire Procedure is 'ii1entiy suited for eonemic' large stale opera range; or aikyl aminesmay be used. est amines, methyl and ethyiarrfines, a e less satisfactory as the solu-' bility while adequate for sbme purposes, is distinctly inferior to thatwhich is obtainable with alkyl amines of greate r chain length. On the other hand; if the chain length is excessive, such as, for example, in fatty aminesof the nature of hexadecyl amine; the tinotorial strength begins to drop off and there is no gain in solubility, Therefore, we prefer not to use arnines having any large content of amines having 16 or more carbon atoms. The range 01f amines from 3 to 6' carbide at ms give the best ,results, the solu m 'tren tHi flh h Hav ng al l' grou s .911 theafr'iin f om" 3 '6 carbon atoms are preferred. or aniyi b anthr'aguindnes; the most important a es 2 methy'l' a'nthra'qifiino'n'e, w rch is rea'lny available commriauy by the ring 01p! sure of para toluyl benzoic .acid, .and isj vejry smattenitratje to: lini'tro fi methyl. 1- to" 1:5 and 1:8-dinitro' 2-n' 'ethyl' anthra' uinone. How ever, other beta alkyl anthra'quinones, such as 2- ethyl anthraquinone, 2-pr0pyl anthraquinone, 2- butyl anthraquinone' can be us'ed, and they even ofier a slight advantage in solubility.

Anthraquinones having long alkyl' side chains may be used but they do not offer any advantage. Therefore, while they are included broadly in the scope of the invention, we prefer beta alkyl anthraduinones inwhich the alkyl group has from 1 o. arbp ietpms. H

tis .nq ecessar 93 Pete e.l ..afi. in; ast; it spi eee dvefitase o use m' ef s of various isomeric'o'r homologous alkyl amines. sue; m tures aiv .rrqdu. s.e ashame sel li most.a lnat .stasis, an s them cte i .re i es e a q amer nm tu .:9 mqn am l; am nesr95. entail. a.- th a u en i cqns i bl mer wer then thedyeobtainedfrom pure normal amyl amine; The reaction is best carriedout in aromatic solvents, such as benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, etc. The chlorinated benzenes are particularly suited because of their good solvent action on the nitro alkyl anthraquinones. The reaction proceeds readily at temperatures of 80 to 120 C., and no superatmospheric pressure is required.

The invention is illustrated by the following examples, in which the parts are by weight.

Example 1 NHCEHH 20 parts of l-nitro-Z-methylanthraquinone and 26 parts of amylamines (mixed isomers) are charged into a vessel containing 90 parts of orthodichlorobenzene. The mixture is heated under. reflux with stirring for 8-10 hours. The solution gradually assumes a deep red color and practically all of the solid dissolves.

The solvent and excess amylamine are removed by steam distillation. The residue is cooled to 35-40 C., and 160 parts of carbon tetrachloride are added and after stirring for a short time, the mixture is filtered. The organic layer in the filtrate is separated and the carbon tetrachloride is removed from the dye by distillation. The last traces of solvent may be removed in vacuo, or by heating the oil in pans. The product is a deep red liquid or buttery solid readily soluble in mineral oil. The yield is practically quantitative.

Example 2 Nnomonzcmom 80.1 parts of 1-nitro-2-methylanthraquinone and 109.5 parts of n-butylamine and 300 parts of orthodichlorobenzene are charged into a reaction vessel and the mixture is heated under reflux with stirring for 16 hours. The mixture is steam distilled free of orthodichlorobenzene and excess butylamine, cooled, filtered, and washed well with water.

The resulting product, a low-melting solid, is a red dye soluble in organic solvents Example 3 NHCEgCHzCHzCHzCHzCH;

Example 4 NHC5H1;

5 parts of l-nitro-Z-ethyl anthraquinone, and 6.2 parts of a commercial mixture of isomeric mono-amylamines, are placed in 19.5 parts of orthodichlorobenzene and the mixture is heated under reflux with stirring for 16'hours. The solvent and excess amine are removed by steam distillation. The residual oil is taken up in 40 parts of carbon tetrachloride, the mixture is filtered and the layers are separated. The carbon tetrachloride is removed from the dye by distillation. The resulting product is a viscous red liquid readily soluble in mineral oil.

Example 5 NHCEHH Hum-NH NHCsHn C 0 v o 0 CH3 CH3 NHOsHn 20 parts of the mixture of 1,5 and 1,8-dinitro- 2-methylanthraquinone (obtainable by the dinitration of Z-methylanthraquinone) and 42 parts of a commercial mixture of mono-amylamines are charged into 104 parts of orthodichlorobenzene. The mixture is heated under reflux with stirrin for 3 hours. The mixture is then'steam distilled. The residual red-violet oil is taken up in parts of carbon tetrachloride. The mixture is clarified and the layers in the filtrate are separated. The carbon tetrachloride is removed by distillation. The product is a red oil, giving a blue-red to violet solution in mineral oil and other organic solvents.

We claim:

1. Z-methyl-l-amylamino anthraquinone.

2. A mixture of the isomeric 2-methyl-1,5-di- (amyl amino) and. 2-methyl-1,8-di-(amylamino) anthraquinone.

3. 2-alkyl-1-alkylaminoanthraquinones and mixtures thereof having the following formula (I? LIIHR o NnR in which R is an alkyl group containing from 3 to 6 carbon atoms, and X is selected from the group consisting of --I-I and NI-]IR., at least one X being hydrogen,

5. A process of preparing 2-alkyl-l-alkylaminoanthraquinones and mixtures thereof having the following formula o NHR X l X l O drocarbons and chlorinated hydrocarbons of the benzene series.

6. A process of preparing 2-methyl-1-a1ky1- aminoanthraquinones having the formula NHR X ll in which R is an alkyl group containing from 3 to 6 carbon atoms, and X is selected from the group consisting of H and NHR, at least one X being hydrogen, which comprises reacting the corresponding l-nitro 2 methylanthraquinone with the corresponding alkylamine in an aromatic solvent selected from the group consisting of hy- 6 drocarbons and chlorinated hydrocarbons of the benzene series.

7. A process of preparing a mixture of the isomeric 1,5-di-(alkylamino)-2-methyland 1,8-di- (alkylamino) 2 methylanthraquinones having the following formula 0 NHR X ll in which R is an alkyl group containing from 3 to 6 carbon atoms, and X is selected from the group consisting of H and -NHR, at least one X being hydrogen, which comprises reacting a mixture of 1,5 and 1,8 dinitro 2 methylanthraquinone with the corresponding alkylamine in an aromatic solvent selected from the group consisting of hydrocarbons and chlorinated hydrocarbons of the benzene series.

8. A process according to claim 6 in which the alkylamine is an amylamine.

9. A process according to claim 7 in which the alkylamine is an amylamine.

MARIO SCALERA. WILLIAM B. HARDY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,205,191 Flaks June 18, 1940.

FOREIGN PATENTS Number Country Date 144,634 Germany Sept. 1, 1903 

